Sensors can generally be employed to detect when a particular event occurs. For instance, sensors can be used to detect when a target pressure, temperature, or sound occurs. Some sensors can detect proximity to an object or person. Other sensors can detect speed or the location of an object. Such sensors can be implemented in a number of technologies, including infrared, radar, and seismic technologies. Some sensors can be implemented with a combination of such technologies (e.g., infrared proximity and seismic sensors).
Remote sensors have numerous applications in both the military and commercial arenas. Such applications include detecting intrusion into a secure room or facility, personnel movement, vehicle speed, and perimeter breach of a field position. Typically, remote sensors are deployed in an area to be monitored. The location of each sensor is noted. The deployed sensors are communicatively coupled to a remote collection site where transmitted sensor signals can be interpreted. In this way, when the area being monitored experiences activity, that activity can be detected and appropriate action can be taken.
Correctly noting the location of each deployed sensor is essential. Otherwise, interpreting the sensor signals received at the remote location will be difficult if not impossible, particularly where a large number of sensors are deployed over a large area. Consider, for example, the case where ten or more sensors are deployed on several floors of a multi-story building having multiple entrances/exits. Transmissions from each sensor must be associated with a particular location within the building for the data to have specific meaning (e.g., how many personnel on each floor, how many personnel have entered/exited a particular floor).
Noting the location of each sensor is not a trivial task. If a reasonable number of sensors are deployed, their respective locations can be maintained in the memory of the person who deployed them. Another technique is to program the location of each sensor into a central computer database (e.g., PDA or base station). Activity detected by the sensors included in the database can be indicated via a graphical user interface or other display that shows sensor locations. Such sensor location methods are associated with a number of problems.
For instance, there are clear difficulties associated with an individual attempting to remember the location of multiple sensors. Faulty memory and stressful conditions under which total recall is required render this manual technique impractical for many applications. Moreover, each sensor typically transmits on a unique channel or path, so that one sensor output can be distinguished from another. As such, substantial communication bandwidth may be required. To accommodate the unique transmission scheme, each sensor must have a unique transmitter configuration, thereby increasing manufacturing complexity and cost.
With respect to sensor database techniques, entering sensor location information into a computer or similar device requires not only data entry (which is time consuming and prone to human error), but also requires the user to carry that input device. This added baggage is in addition to the sensors for deployment and any other necessary equipment (e.g., weapon, munitions, 2-way radio) that must be carried by the user. Although the data entry burden can be reduced with customized in-intake algorithms and user-friendly graphical user interfaces, such techniques add complexity and cost to the overall design of the remote sensor system. Other techniques that further automate the deployment process so as to reduce the problems associated data entry add further complexity and cost, and are more difficult to use.
What is needed, therefore, are low cost and complexity remote sensing techniques where sensors can be easily deployed and monitored, with minimal opportunity for human error.